Food-warming devices are used in the fast food industry to keep freshly prepared food products warm for several minutes. Prior art food-warming devices have engulfed the food products with warm air for up to ten minutes without serious degradation of quality of the food product. An important feature is to keep the food products visible to customers for selection purposes.
One example of a prior art food-warming device is disclosed in U.S. Pat. No. 4,822,981. This device has an inclined heated plate upon which food is held. A plurality of infrared heating lamps are disposed over the plate to provide heated air directed downwardly onto the food. A disadvantage of this prior art food-warming device is that the heat lamps visibly give the impression of a food-warming device. This can give a customer an impression that the food product was cooked sometime ago and has been warmed for an indefinite time.
Another prior art food-warming device comprises an enclosed sandwich bin that has open front and rear service openings. To insulate the bin from heat loss to ambient atmosphere, a warm air circulating system provides moving air curtains for the front and rear service openings. An example of this type of food-warming device, shown in U.S. Pat. No. 3,942,426, diffuses some of the recirculating air into the bin to maintain a bin temperature well above ambient temperature. However, there is relatively little air motion in the bin. The device also includes an air chamber through which ambient air may pass by convection to keep a wall of the device cool to the touch. This food-warming device has a top and two sides that conceal the food products from the customer's view.
Another prior art enclosed sandwich bin type of food-warming device, One example of this type of food-warming device, shown in U.S. Pat. No. 4,437,396, directs the recirculating air away from the service openings and into the bin to form a dome of hot, moist air above the sandwiches. Again, this food-warming device has a top and two sides that conceal the food products from the customer's view.
Other prior art food-warming devices that use recirculating hot air to heat or warm food products are shown in U.S. Pat. Nos. 4,233,495, 4,327,279, 4,455,478 and 5,276,309. However, these food-warming devices have chest type enclosures that conceal the food products from the customer's view.
Another prior art food-warming device applicable to a food-warming table such as used in cafeterias is disclosed in U.S. Pat. No. 4,038,968.
This device employs a food holding pan that fits in a receptacle contained directly within the table. The pan is heated from below by an electrical heater. A moving air stream is circulated across the top of the pan to retard loss of heat and prevent moisture from leaving the food. The air stream picks up heat and moisture that rises from the food products. This device, being designed for use in a cafeteria, is unsuitable for use in a fast food restaurant.
What is needed is a food-warming product that has no visible heat source, but yet holds the food products visible to customers.
The present invention provides a food-warming device having a food product bin that holds food products that are visible, but yet does not have any visible heat emitting sources, such as overhead heating lamps.
The present invention provides a method of warming food by a combination of heat supplied by a heated plate and heat supplied by a circulating stream of heated air. The circulating stream of heated air contacts the food products with warm air as well as provides a barrier to heat and moisture loss to ambient air.